1. Field of the Invention
This invention relates generally to stator assemblies for dynamoelectric machines and methods of making the same, and more particularly to a stator assembly for a motor used in a hermetic motor-refrigeration compressor assembly, and the method of making the same.
2. Description of the Prior Art
In the past, it has been conventional practice to hold the laminations comprising a dynamoelectric machine stator core member in assembled relation by riveting, cleating or welding prior to placing the field windings in the slots of the core member. In the case of a hermetic motor used in a hermetically sealed motor-refrigeration compressor system, the stator core member is typically bolted to the compressor with an end face of the core member engaging a surface on the compressor, the stator core member thus being supported in cantilever-fashion. It is of course essential that there be close concentricity between the rotor member and the bore of the stator core member and thus, in such hermetic motor applications, it is essential that the end face of the stator core member which abuts the compressor surface be perpendicular to the bore; however, with such prior riveted, cleated or welded stator cores, there has been a tendency for the stator core to sag or tilt after mounting, or during handling prior to mounting, thus adversely affecting the rotor-bore concentricity. To overcome this problem, it is known, as described for example in U.S. Pat. No. 3,490,143, to bond the stack of stator laminations together to form, in essence, an integral structure. However, such stator core member bonding adds appreciably to the cost of the motor. It is also known, as described for example in U.S. Pat. No. 3,493,794, to use the windings themselves to hold the stator core laminations in assembled relation, a sleeve providing the requisite rotor-bore concentricity during attachment of the stator core member to the compressor. While such a structure and method may be satisfactory for shorter stack heights, such as up to about one inch, it is subject to the same sagging or tilting problem in longer stack heights.
U.S. Pat. No. 3,745,138 discloses a so-called self-bonding magnet wire, i.e., a magnet wire having a coating which, following formation of a coil from the wire, permits bonding the entire coil by heating the same.